E.g.f.: exp(-2*x) / (1-x)^2.

Terms

a(0) =1a(1) =0a(2) =2a(3) =4a(4) =24a(5) =128a(6) =880a(7) =6816a(8) =60032a(9) =589312a(10) =6384384a(11) =75630080a(12) =972387328a(13) =13483769856a(14) =200571078656